5月6日，《神經(jīng)科學(xué)》（Journal of Neuroscience）發(fā)表了中科院上海生科院神經(jīng)科學(xué)研究所章曉輝研究員課題組的研究發(fā)現(xiàn)——“節(jié)律的感覺(jué)輸入調(diào)制大腦中神經(jīng)網(wǎng)絡(luò)活動(dòng)的振蕩頻率”,。博士研究生高麗霞,、葉昌泉等通過(guò)對(duì)整體動(dòng)物的電生理研究，發(fā)現(xiàn)丘腦中一種頻率小于1 Hz的慢波振蕩（slow oscillations）的活動(dòng)節(jié)律可以被聲音刺激的節(jié)律所調(diào)制,。時(shí)間間隔為秒的節(jié)律聲音的短時(shí)間刺激可以促使丘腦慢波振蕩活動(dòng)的自發(fā)頻率“跟隨”外界聲音刺激頻率,，并且在撤除刺激后，丘腦的自發(fā)振蕩活動(dòng)仍能保持聲音刺激頻率達(dá)數(shù)個(gè)振蕩周期（約幾十秒）,。同時(shí),，這種慢波振蕩的“跟隨效應(yīng)”也能特異地增強(qiáng)神經(jīng)元對(duì)相同時(shí)間間隔的弱聲音的反應(yīng)，這一易化作用則可維持達(dá)十幾分鐘,。這些研究發(fā)現(xiàn)揭示了一種與感覺(jué)輸入特征相關(guān)的神經(jīng)網(wǎng)絡(luò)活動(dòng)的可塑性,，也提示節(jié)律刺激對(duì)慢波振蕩發(fā)生頻率的調(diào)制可能參與編碼和短時(shí)記憶“秒級(jí)”時(shí)間間隔信息。
大腦中許多功能區(qū)呈現(xiàn)不同形式的神經(jīng)網(wǎng)絡(luò)振蕩活動(dòng)（oscillatory brain activity）,，它們反映群體神經(jīng)元的同步活動(dòng)以及大腦的不同功能狀態(tài),。例如，在清醒工作狀態(tài)下,，振蕩活動(dòng)多表現(xiàn)為高頻低幅,；在睡眠狀態(tài)下，振蕩特征多為低頻高幅,。這些不同形式的振蕩活動(dòng)分別在大腦處理,、傳遞和整合感覺(jué)信息，鞏固記憶,，以及一些高級(jí)認(rèn)知活動(dòng)（如注意行為）中發(fā)揮重要的作用,。其中，調(diào)制神經(jīng)網(wǎng)絡(luò)活動(dòng)的振蕩特性是實(shí)現(xiàn)這些腦功能的可能機(jī)制之一,。
該工作是在神經(jīng)科學(xué)研究所蒲慕明教授和香港理工大學(xué)賀菊芳教授的課題組共同協(xié)作下完成,，并受到中科院“創(chuàng)新項(xiàng)目”的資助。（生物谷Bioon.com）
生物谷推薦原始出處：
The Journal of Neuroscience, May 6, 2009, doi:10.1523/JNEUROSCI.5733-08.2009
Entrainment of Slow Oscillations of Auditory Thalamic Neurons by Repetitive Sound Stimuli
Lixia Gao,1 Xiankai Meng,2 Changquan Ye,1 Haitian Zhang,1 Chunhua Liu,1 Yang Dan,3,4 Mu-ming Poo,1,3 Jufang He,2 and Xiaohui Zhang1
1Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China, 2Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hong Kong, China, and 3Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute and 4Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, California 94720
Correspondence should be addressed to either of the following: Jufang He, Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China; or Xiaohui Zhang, Institute of Neuroscience, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
Slow oscillations at frequencies <1 Hz manifest in many brain regions as discrete transitions between a depolarized up state and a hyperpolarized down state of the neuronal membrane potential. Although up and down states are known to differentially affect sensory-evoked responses, whether and how they are modulated by sensory stimuli are not well understood. In the present study, intracellular recording in anesthetized guinea pigs showed that membrane potentials of nonlemniscal auditory thalamic neurons exhibited spontaneous up/down transitions at random intervals in the range of 2–30 s, which could be entrained to a regular interval by repetitive sound stimuli. After termination of the entraining stimulation (ES), regular up/down transitions persisted for several cycles at the ES interval. Furthermore, the efficacy of weak sound stimuli in triggering the up-to-down transition was potentiated specifically at the ES interval for at least 10 min. Extracellular recordings in the auditory thalamus of unanesthetized guinea pigs also showed entrainment of slow oscillations by rhythmic sound stimuli during slow wave sleep. These results demonstrate a novel form of network plasticity, which could help to retain the information of stimulus interval on the order of seconds.
